It is known in the art of treating blood, that blood may be collected and filtered, whereby bone fragments and other debris in the blood may be removed from the blood, with the blood then being returned to the patient for infusion. An example of such a process and apparatus is disclosed in U.S. Pat. No. 4,781,707, the complete disclosure of which is herein incorporated by reference.
It is also known to remove insoluble fats (or lipids) from blood prior to re-transfusing the blood to a patient. Examples of such techniques are disclosed in U.S. Pat. Nos. 5,203,778 and 5,354,262, the complete disclosures of which are likewise herein incorporated by reference. Other examples of blood treatment for re-use of the blood reside in U.S. Pat. No. 5,133,703, the complete disclosure of which is also herewith incorporated by reference.
It is also known that, prior to infusion of blood to a patient, one may remove certain components of the blood, for example, by centrifuge techniques, before infusing the remaining blood or plasma to the patient. Examples of substances that might be removed from the blood before the blood is re-transfused to the patient might be saline, proteins, and other substances that are not desired to be infused in quantity. Such substances might also include surgical irrigants, pharmaceuticals, extracellular proteins, bile, gastric fluids, fat liquids and fat particles, cellular debris, blood clots, clumped cells, tissue, coagulation byproducts, cancer cells or other potentially harmful substances. The removed components may be passed to waste. Upon reintroduction of the more greatly desired components of the blood, it is often preferable not to reintroduce some components so the available centrifuge or other separation techniques may serve to separate some components from that portion of the blood that is to be infused to a patient. Various other separation techniques have also been used to separate some components of the blood from others before returning the desired components of the blood to a patient for re-transfusion. Many of the existing techniques for separating various components of the blood prior to returning the desired components of the blood to a patient, involve large, expensive equipment and specialized technicians to operate it, including but not limited to centrifuge type equipment and the like, whereby treating physicians may find that such equipment is in use by others when they desire to use the same for their own patient, and consequently it may occur that where separation of blood components is desired such might not occur due to the unavailability of the equipment for use. In other circumstances, because of the cost of the equipment for doing the blood separation, hospitals might not have such equipment on hand, and again, the desired separation of various components of the blood may not occur prior to infusion. Existing membrane systems have been unsuccessful due to fouling and lack of speed. They are typically used for small laboratory sample quantities. Such are generally of the centrifugal washer type. In some situations, as for example in emergencies, the capacity and speed of single centrifugal washers may be limited.
The present invention is directed toward providing simple, low-cost, single use disposable collection and processing equipment and a method of providing and using the same, whereby many units of such equipment may be maintained, readily on hand at a hospital or the like, for single use and then to be discarded.
The present invention allows running a number of units or cell washers together, for example, arranged in parallel.
The present invention is also directed to providing blood separation techniques whereby microporous membranes may be used to treat the blood and membrane protection devices are used to protect the membrane. The treatment can reside in separation from the red blood cells those components of larger and smaller size, including the more watery components. Optionally, the treatment of the blood can reside in delivering other substances to the blood.
The present invention is also directed toward providing a novel filter, for independent use, as well as for protecting a microporous membrane that is to be used for processing blood, from being fouled, which prior art techniques have had difficulty in protecting, and to maintain clinically acceptable speed of separation.
The present invention is also directed toward providing a novel pump, for independent use as well as for recirculating blood along a microporous membrane.
The present invention is also intended for processing under conditions of minimum blood volume as well as under conditions in which a minimum volume is lost or captured in the filter (hold-up volume). Thus, the present invention is practical for pediatric and small blood loss cases which are problems which plague the centrifuge type systems, because of their large holdup (wasted) blood volumes.